This invention relates generally to a method and apparatus for viewing and interacting with a real world item such as a page, with a virtual display of imagery and/or text to give the illusion of holding a printed version of an electronic document without actually printing the displayed document. In augmented-reality, some form of physical display such as glasses, goggles or a helmet-mounted display is used to project or superimpose a computer-generated image onto the user's view of the real world. The system analyzes the viewer's image in real-time and adjusts the computer-generated image to correspond with the actual view. Such interaction combines some of the feel and function of a real item such as paper (holding it, writing on it) with the capabilities of an electronic document (dynamic, interactive). However, it would be appreciated to those of ordinary skills in the art that the invention could be readily adapted for use in other environments as, for example, where similar imaging methods are advantageously associated with other reality items for other purposes than displaying a document.
The ubiquitous use of PC workstations and the capabilities of the World Wide Web are leading to the use of electronic documents and the inclusion of dynamic components such as hyperlinks and video. These electronic documents are often not compatible with the static requirements of paper prints. Yet people still prefer paper for reading long documents, and paper is easily annotated and portable. There is a need for a display mechanism that combines the desirable properties of static paper and the dynamic capabilities of a CRT or LCD display. Research towards that goal includes work on Portable Document Readers and Electric Paper. This invention relates to an alternative approach based on the idea of augmented-reality.
In augmented-reality, a video camera can be used to provide the computer with the same view as seen by a user, then a computer-generated image is superimposed on that view. This is not virtual-reality where the user is immersed in a totally synthetic, computer-generated environment. Rather, augmented-reality is a combination of the synthetic computer-generated image superimposed upon an every day object of the real world.
Although augmented-reality display systems are known, they have had limited applications and usefulness. In particular, the reality portion identified by the video camera has largely been limited to a fixed view of a single setting, which is predetermined and strictly limited as to what may be presented and identifiable from the camera image. In addition, what can then be displayed on this controlled setting is also undesirably limited as to what can be shown, usually just a single image. Interaction with the display is essentially unknown.
As people become more accustomed to electronic, multi-media publishing as an alternative to conventional publishing on paper, there is a substantial need for more convenient and improved interactive control to enhance the freedom, variety and quality of display imagery in a user environment that is comfortable, convenient and easily controllable with regard to the viewing of an electronic display. Prior known application programs for electronic publishing are incompatible with augmented-reality display systems. Such programs are more accustomed to instruction processing comprising mouse, keyboard or button press representations for user instructions. There is a particular need for an application program that can recognize and translate convenient user commands in an augmented-reality setting, i.e., paper manipulation, hand and finger gestures, selected voice commands, in a real-time processing setting, for the improved interactive display scheme envisioned above.
Another particular problem needed to be solved with regard to augmented-reality display systems is a dependable system for recognizing certain preselected objects within the view plane of the image. For example, if the user intends to utilize a piece of paper as a reference plane for the augmenting display, distinguishing the piece of paper from other objects in the image having common characteristics to the paper is a certain problem. If the view plane could be controlled to provide a distinguishable background behind a single piece of paper, the distinguishing problem is simplified. However, if the background is a compilation of different items, such as commonly occur on a desk or work surface, i.e., desk pad, envelopes, file folders, coffee cups, or even a shirt sleeve cuff of a user, all of which can appear in the viewing plane as having straight edges and corners, then the real world concern of identifying a particular piece of paper can be readily appreciated. The problem more specifically involves converting images having two-dimensional characteristics common with a paper page as seen in a view plane to a corresponding three-dimensional object, and then verifying whether that object is reasonably consistent with a piece of paper.
The present invention contemplates coordinating a synthetic image with a real one with particular application to the display of documents comprising text and images so that the real image can be a piece or plurality of pieces of paper that the user can access. The user can manipulate electronic documents augmented with the pieces of paper, in a manner to organize them by the natural mechanism of selective positioning and movement of the pieces of paper. A scaling of the image is controlled by positioning of the paper relative to the eyes of the user so that the user is not confined to the limited screen space of a CRT or LCD display, but can have many documents available (analogous to a multi-window electronic display) by just turning the head from one piece of paper to another. Movement between different documents or images is easily realized by accessing of displayed hyperlinks. Such a system is readily adaptable to a plurality of uses with reality references of a variety of dimensions and characteristics, and which provides improved communicative and interactive capabilities between a user and a computer display system with a selective variety of interactive tools that are comfortable and convenient for the user.
The present invention further contemplates verifying the presence of a preselected object intended for use as a reference tool by a user such as a standard piece of paper, so that the reference tool is readily distinguishable from the plurality of real world items that are commonplace in a work setting.